1. Field of the Invention
The present invention relates to devices for extracting a tissue sample from a subject, such as for implementing a biopsy of a breast.
2. Description of the Prior Art
In a biopsy a tissue sample is extracted—for example from the tissue of a breast of a patient—for histological examination. The extraction of the tissue sample can take place with the assistance of imaging methods. An overview volume set of the breast is created with a tomosynthesis method. X-ray images of the breast are acquired to create the overview volume set. For x-ray image acquisition, an x-ray tube is moved (for example in an orbit) over a detector. For example, in a tomosynthesis procedure the x-ray tube moves in an angle range from +25° to −25°. An x-ray radiation in the x-ray source is then triggered at regular intervals, and the respective x-ray image is read out and buffered by the detector. An overview volume set is subsequently created from the multiple projections that are present in digital image data. Regions for the extraction of a tissue sample are localized in the overview volume set, and from this the coordinates are determined for the entry position, direction and depth of a biopsy needle. The biopsy needle is introduced into the breast for tissue extraction. Since an exact fixing of the breast between the detector and a compression plate can be maintained only with great difficulty over the entire examination duration, and the tissue variation to be removed is often only a few cubic millimeters in size, a control volume set with a biopsy needle introduced into the breast tissue is created before the extraction of the tissue sample. The alignment and the position of the biopsy needle tip can be checked by means of the data from the control volume set, and an adaptation and alignment of the biopsy needle can be conducted. However, the arrangement entails the disadvantage that parts of the biopsy unit occlude x-ray image information and generate additional artifacts, known as out-of-plane artifacts.